docs: def get_buckets(self, bucket_type=None, timeout=None):
          """
          Serialize bucket listing request and deserialize response
          """
          msg_code = riak.pb.messages.MSG_CODE_LIST_BUCKETS_REQ
          codec = self._get_codec(msg_code)
          msg = codec.encode_get_buckets(bucket_type,
                                         timeout, streaming=False)
          resp_code, resp = self._request(msg, codec)
          return resp.buckets